feat: First version, failing json parse string

1 files changed, 113 insertions, 0 deletions

diff --git a/json.c b/json.c
new file mode 100644
index 0000000..e68d617
--- /dev/null
+++ b/json.c
@@ -0,0 +1,113 @@
+#include "json.h"
+
+#include <assert.h>
+#include <ctype.h>
+#include <math.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "string.h"
+
+typedef struct {
+  int value;
+  uintptr_t pos;
+} parse_integer_result;
+
+parse_integer_result parse_integer(Arena *a, Str src, uintptr_t pos) {
+  int *ints = new (a, int, 16); // TODO: reuse in parsing
+  int i = 0;
+  while (isdigit(src.data[pos + i])) {
+    int val = (src.data[pos + i] - '0');
+    ints[i] = val;
+    i++;
+  }
+  int result = 0;
+  for (int j = 0; j < i; j++) {
+    result += ints[j] * pow(10, (i - j - 1));
+  }
+  printf("json.parse_integer: parsed int=%d at pos=%lu\n", result, pos);
+  return (parse_integer_result){result, pos + i};
+}
+
+uintptr_t absorb_whitespaces(Str src, uintptr_t pos) {
+  int i = 0;
+  while (isspace(src.data[pos + i])) {
+    i++;
+  }
+  return pos + i;
+}
+
+typedef struct {
+  Vec *items;
+  uintptr_t pos;
+} parse_array_result;
+
+parse_array_result parse_array(Arena *a, Str src, uintptr_t start_pos) {
+  printf("json.parse_array: parsing array %s\n", src.data + start_pos);
+  assert(src.data[start_pos] == '[');
+  uintptr_t pos = start_pos + 1;
+  Vec *items = Vec_new(a, JSON, 0);
+  for (;;) {
+    pos = absorb_whitespaces(src, pos);
+    parse_integer_result result = parse_integer(a, src, pos);
+    assert(result.pos > pos);
+    items = Vec_push(a, items, &result.value);
+    pos = result.pos;
+    pos = absorb_whitespaces(src, pos);
+    if (src.data[pos] == ',') {
+      pos++;
+    } else {
+      break;
+    }
+  };
+  assert(src.data[pos] == ']');
+
+  return (parse_array_result){items, pos + 1};
+}
+
+typedef struct {
+  Str string;
+  uintptr_t pos;
+} parse_string_result;
+
+parse_string_result parse_string(Arena *a, Str src, uintptr_t pos) {
+  printf("json.parse_string: %s", src.data + pos);
+  assert(src.data[pos] == '"');
+  int i = 1;
+
+  while (src.data[pos + i] != '"' && src.data[pos + i - 1] != '\\') {
+    i++;
+    assert(i + pos <= src.len);
+  }
+  assert(src.data[pos + i]);
+  char *s;
+  memcpy(s, src.data + pos + 1, i - 1);
+
+  printf("%s", s);
+
+  return (parse_string_result){Str_copy(a, src.data + pos + 1, i - 1), pos + i};
+}
+
+JSON JSON_parse(Arena *a, Str src) {
+  JSON json = {0};
+  int pos = 0;
+  // printf("json.parse: src=%s", src.data);
+  if (isdigit(src.data[pos])) {
+    parse_integer_result result = parse_integer(a, src, 0);
+    json.integer = &result.value;
+    pos = result.pos;
+  }
+  if (src.data[pos] == '[') {
+    parse_array_result result = parse_array(a, src, pos);
+    json.array = result.items;
+    pos = result.pos;
+  }
+  if (src.data[pos] == '"') {
+    parse_string_result result = parse_string(a, src, pos);
+    json.string = &result.string;
+    pos = result.pos;
+  }
+
+  return json;
+}